ExtraRewardsDistributor deposits don’t work with fee-on transfer tokens

Lines of code Vulnerability details Impact There are ERC20 tokens that may make certain customizations to their ERC20 contracts. One type of these tokens is deflationary tokens that charge a certain fee for every safetransfer or safetransferFrom . Proof of Concept The ExtraRewardsDistributor’s...

Griefing attack by transferring aTokens to the contract

Originally part of a QA report by Tadashi 69 Griefing attack by transferring aTokens to the contract Summary: tokenToShares uses the following formula for computing the total shares of an user: return supply == 0 ? tokens : tokens.mulsupply.divaToken.balanceOfaddressthis; An attacker wishing to...

Possible lost msg.value

Lines of code Vulnerability details Impact Possible lost value in depositCollateral function call Proof of Concept In call depositCollateral can will send value and the asset can be an ERC20!= address0, if LidoVault and ConvexCurveLPVault contract receive this call the fouds will lost Also in...

ConvexCurveLPVault's _transferYield can become stuck with zero reward transfer

Lines of code Vulnerability details Now there are no checks for the amounts to be transferred via transferYield and processTreasury. As reward token list is external and an arbitrary token can end up there, in the case when such token doesn't allow for zero amount transfers, the reward retrieval...

YearnTokenAdapter's wrap can become stuck as it uses one step approval for an arbitrary underlying

Lines of code Vulnerability details Some tokens do not allow for approval of positive amount when allowance is positive already to handle approval race condition, most known example is USDT. This can cause the function to stuck whenever a combination of such a token and leftover approval be met...

Use ERC721.safertransferFrom instead of ERC721.transferFrom when you send out NFT

Lines of code Vulnerability details Impact Buyers can accidentally lose their NFT if they send to incorrect address. Proof of Concept When the buyer decide to call exercise the NFT is transfered using transferFrom. This is risky because if the destination msg.sender is a contract and it is unable...

“No Revert on Failure“ tokens can be stolen from the contract by disguising them as NFTs.

Lines of code Vulnerability details Impact If a user creates a vault with an ERC20 token with the following two properties: 1. There’s a way to make transferFrom fail to transfer tokens without reverting e.g. some tokens like ZRX return false on failure instead of reverting. 2. fransferFromfrom,...

Fee-on-transfer / rebasing ERC20 cannot be used as underlying

Lines of code Vulnerability details Some ERC20 tokens may have fee-on-transfer or change balance without owner intervention. If these tokens are used as underlying in the protocol they can be lost. Proof of concept Alice creates a vault with a token that has a 1% fee on transfer. She sends...

TokenType mismatch with true type can be exploited to steal funds

Lines of code Vulnerability details A vault can be created for different TokenTypes, namely ERC20 and ERC721. These tokens have different logic, so a user needs to pass the type of the underlying token when creating a vault. At the end of createVault the user's tokens are pulled into the contract...

[WP-H0] Fake balances can be created for not-yet-existing ERC20 tokens, which allows attackers to set traps to steal funds from future users

Lines of code Vulnerability details function createVault uint256 tokenIdOrAmount, address token, ... external returns uint256 vaultId ... Vault memory vault = Vault ... ; // vault index should always be odd vaultIndex += 2; vaultId = vaultIndex; vaultsvaultId = vault; // give msg.sender vault tok...

Cally does not support ERC20 tokens with built-in fee

Lines of code Vulnerability details Impact Contract Cally does not properly handle ERC20 tokens that charge fee on their transfers. Implementation of such a tokens does not transfer exact amount provided to transfer but part of it is charged as a fee, burned or used in some other way. This leads ...

Payble function allows for Eth transfer even when ERC20 tokens are being used

Lines of code Vulnerability details Impact The function depositCollateral in GeneralVault.sol is payable. This needs to be payable for the case in LidoVault where depositToYeild expects ETH to be transferred. However for the ConvexCurveLPVault.sol and the case when LidoVault is not using Eth as a...

createVault() does not verify ERC20 token contract exists before transferring

Lines of code Vulnerability details Impact There are no checks to ensure the the vault.token contract exists when creating a vault. Token address are deterministic in the EVM and can be known ahead of time. As a result it is possible for a user to call createVault with token set to a ERC20 contra...

Malicious ERC20 or ERC777 could be used as collateral

Lines of code Cally.solL296 Vulnerability details Impact A malicious ERC20 or ERC777 could be used as collateral and rug the exerciser on exercise through a malicious implementation of ERC20vault.token.safeTransfer. Proof of Concept Any ERC20/ERC777 token is accepted as there is no whitelist. Thi...

no-revert-on-transfer ERC20 tokens can be drained

Lines of code Vulnerability details Impact Some ERC20 tokens don't throw but just return false when a transfer fails. This can be abused to trick the createVault function to initialize the vault without providing any tokens. A good example of such a token is ZRX: Etherscan code When such a vault ...

A malicious user can create a vault that is actually empty

Lines of code Vulnerability details description A malicious user can call the createVault function to create a vault with an ERC20 token that returns false rather than revert on failed transfer. By specifying the tokenType parameter to be ERC721 the transferFrom function will be called rather tha...

Gravity does not support ERC20 tokens with built-in fee

Lines of code Vulnerability details Impact Contract Gravity.sol does not properly handle ERC20 tokens that charge fee on their transfers. Implementation of such a tokens does not transfer exact amount provided to transfer but part of it is charged as a fee, burned or used in some other way. This...

Tokens with fee on transfer are not supported

Lines of code Vulnerability details There are ERC20 tokens that charge fee for every transfer or transferFrom. In the current implementation, sendToCosmos assumes that the received amount is the same as the transfer amount, and uses it to emit SendToCosmosEvent event. As a result, when bridging t...

Centralisation Risk: Admin can withdraw all ERC20 held in the bridge and all deployed CosmosERC20 tokens

Lines of code Vulnerability details Impact The function withdrawERC20 allows an admin to withdraw any ERC20 tokens help in the bridge. The impact of this is significant as the function deployERC20 will create a new CosmosERC20 token with MAXUINT256 supply minted to the Gravity smart contract. The...

Consistently check account balance before and after transfers for Fee-On-Transfer discrepancies

Lines of code Vulnerability details Impact Wrong amount emitted in SendToCosmosEvent event Proof of Concept File: Gravity.sol 595: function sendToCosmos 596: address tokenContract, 597: bytes32 destination, 598: uint256 amount 599: public nonReentrant 600:...